Connecting device for operators  telephones



(No Model.)

L. MANN.

QONNEOTING DEVICE FOR OPERATORS TELEPHONES, N0. 266,853 I Patented Oct. 31, 1882.

Aftorn'ey ATENT FFICE.

LEWIS MANN, OF DETROIT, MICHIGAN.

CONNECTING DEVICE FOR OPERATORS TELEPHONES.

SPECIFICATION forming part of Letters Patent No. 266,853, dated October 31, 1882.

Application filed February 20, 1882. (No model.)

To all whom it may concern Be it known that I, LEWIS MANN, of Detroit, county of iVayne, State of Michigan, have invented a new and useful Improvementin Gonnecting Devices for Operators Telephones; and I do hereby declare the following to be a full, clear, and eXact description of the invention, such as will enable others skilled in the art to which it pertains to make and use it, reference beinghad to the accompanying drawings, which form a part of this specification.

My invention relates to aplug which is to be connected to the flexible connecting-cords of a switch-board-operators telephone; and its object is to enable the operator to connect his telephone in circuit with two connected subscribers lines or disconnect it therefrom without interrupting conversation which may at the time be going on over said lines. The purpose of the operators connection in the circuit is to ascertain whether or not communication has been properly established over the two lines, or if a conversation between two subscribers has been concluded.

My connecting-plugisintended especially for use in a telephone-exchange system invented by me, and for which I have applied for Letters Patent in an application filed February3, 1882, Serial No. 51,772; but it may be used in connection with anyswitch-board having lineterminals arranged substantially as hereinafter described, and as shown in the accompanying drawings, in which- Figure l is a view, partly in section and partly in elevation, showing my invention applied to use. Fig.2 is a perspective view, illustrating a modification of the invention applied to use. Fig. 3 is a perspective view ofthe modified plug detached.

Referring to Fig. 1, the letter A designates the connecting-plug, which is composed of a handle, (1, having a laterally-extended base, a, of non-conducting material, and the wedgelike metallic terminalsb Z) and b b project in pairs from said base, the terminals of each pair being insulated from each other, and the two terminals 1) I) connected by a wire, 0. The connecting-cords d d of the operators telephone D are connected to the terminals 1) and b respectively, said cords being for convenience passed through apertures formed for them in the handle a and base a.

The letters E E indicate projections from a switch-board which is not shown, and to these projections are attached the terminal metallic springsff and f f The springsf andf are terminals of subscribers lines, and, when not separated by the plug, are in contact with each other, as indicated by dotted lines, so that any two subscriberslines which may be connected with said springs will be connected in circuit. The springs f and f are respectively connected with a transmitter (shown at G) by wires 9 and g.

The devices by means ot'which two subscribers lines may be connected with the springsf and f are shown in my application before re ferred to, and form no part of the present invention. I have, however, indicated the subscribers lines connections in dotted lines, as shown at L and L.

The plug A is shown as applied to enable the operator to connect his receiving-telephone D and the transmitter G in circuit with the two subscribers lines without interrupting any communication which may be in progrcss over said lines; and it will be seen that a circuit is establishcd say from line L over springf, plug-terminal I), cord (1, through telephone I), over cord (1, plug-terminal 1), spring f wire 9, through the transmitter Gr, over wire g, springf plug-terminal b wire 0, plugterminal I), and springf to line L. The operator may listen and learn it a conversation is going on over the lines, and it so may remove his plug without interrupting the same, as the two springsfandj" will immediately come together, as shown in the dotted lines, and thus maintain the communicating-circuit intact. It the subscriber on one of the lines should break circuit and the operator wish to communicate with the other subscriber, he may do so by connecting the spring which formed the terminal of the line which is broken with the ground by any convenient means.

In the modification shown in Figs. 2 and 3 the metallic plug-terminals I) b and D I)" are mounted upon an insulating-plate, a provided terminals of the respective pairs. The termiwith a handle, a the said plate separating the Ico nals b and b" are connected by a wire, 0, and in Fig. 2 the terminals b and b are respectively connected with the receiving-telephone D. This modified form of the connecting-plug A is for use with a switch-board having its pairs of terminal springs for subscribers lines and transmitter secured to the same projection,as shown at E The line-terminal springs are indicated byf and f and the transmitterterminals by f and f. The connection between the lines L L when the plug is inserted between the springs, will be readily understood from the previous description of Fig. 1.

What I claim is- 1. The connecting-plug consisting of the four metallic contact-terminals arranged in two pairs projecting from a non-conducting base, a single terminal of one pair being in electrical connection with a single terminal of the other pair, and the other two terminals adapted for connection with a telephone, substantially as described.

2. The plug consisting of base a, of non-conducting material 'and having a suitable handle, and the pairs of metallic terminals 1) b and b b projecting from said base, the terminals 1) and I) being electrically connected, substantially as described.

3. Thecom'binatiomwith the terminal springs connecting subscribers lines and the terminal springs of the transmitter, of the connectingplug having fourmetallic terminals arrangedin pairs forinsertion between the pairs of springs, respectively, substantially as described.

In testimony whereofl sign this specification in the presence of two witnesses.

LEWIS MANN.

Witnesses:

J. EDWARD WARREN, I CHARLES MANN. 

